- Accept hard upper limit (maxLen) instead of pre-subtracted value
- Caller now passes actual platform limit (e.g., 2000 for Discord)
- Internal buffer of 500 chars is handled within message.go
- Preferred split at maxLen - 500, may extend to maxLen for code blocks
- Never exceeds maxLen, no more mental math for callers
- Move FindLast, findLast, and SplitMessage from discord.go to pkg/utils/message.go
- Update discord.go to use utils.SplitMessage()
- Makes splitting logic reusable across other channels